Maximum length of time until the line of credit matures.

No definition available.

Name:	ffic_LineOfCreditMaturityMax
Namespace Prefix:	ffic_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Loan commitments expiration period.

+ References

No definition available.

+ Details

Name:	ffic_LoanCommitmentsExpiration
Namespace Prefix:	ffic_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the amount of cash required to fully fund agreements to provide credit to borrowers.

+ References

No definition available.

+ Details

Name:	ffic_LoansAndLeasesReceivableCommitmentsCredit
Namespace Prefix:	ffic_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Reflects the weighted average interest rate on commitments to advance to borrowers and lessees at interest rates that increase or decrease depending on certain facts or circumstances.

+ References

No definition available.

+ Details

Name:	ffic_LoansAndLeasesReceivableCommitmentsVariableRatesWeightedAverageRate
Namespace Prefix:	ffic_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the weighted average interest rate associated with agreements to provide advances to borrowers and lessees at stated interest rates.

+ References

No definition available.

+ Details

Name:	ffic_LoansAndLeasesReceivableCommitmentsWeightedAverageRateOfInterest
Namespace Prefix:	ffic_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ffic_Note15CommitmentsandContingenciesDetailsLineItems
Namespace Prefix:	ffic_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

Name:	us-gaap_AreaOfRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of securities, mortgage loans, or other financial instruments pledged as collateral for deposits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 405

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6479006&loc=d3e64164-112818

+ Details

Name:	us-gaap_DepositLiabilitiesCollateralIssuedFinancialInstruments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

No definition available.

+ Details

Name:	us-gaap_LeaseAndRentalExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Term of the lessee's leasing arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the amount of cash required to fully fund agreements to provide advances to borrowers and lessees at stated interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 825

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6480020&loc=d3e61082-112788

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 825

-Section 50

-Paragraph 1

-Subparagraph (b)(2)

-URI http://asc.fasb.org/extlink&oid=6480020&loc=d3e61044-112788

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Reflects the amount of cash required to fully fund agreements to provide advances to borrowers and lessees at interest rates that increase or decrease depending on certain facts or circumstances.

+ References

+ Details

Name:	us-gaap_LoansAndLeasesReceivableCommitmentsVariableRates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

+ Details

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

No definition available.

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_DebtSecurityAxis=ffic_CapitalSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=ffic_LetterOfCreditPledgedAsCollateralMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_HomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfFairValueOfSeparateAccountsByMajorCategoryOfInvestmentAxis=us-gaap_MortgageLoansOnRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=ffic_NewCorporateLeaseAgreementInUniondaleNYMember
Namespace Prefix:
Data Type:	na
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Period Type:

Note 15 - Commitments and Contingencies (Details) (USD $)	12 Months Ended			1 Months Ended	2 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2007	Jul. 31, 2007
Note 15 - Commitments and Contingencies (Details) [Line Items]
Loans and Leases Receivable, Commitments, Fixed Rates	$ 11,600,000
Loans and Leases Receivable, Commitments, Weighted Average Fixed Rate of Interest	4.20%
Loans and Leases Receivable, Commitments, Variable Rates	247,100,000
Loans and Leases Receivable, Commitments, Variable Rates, Weighted Average Rate	3.65%
Loan Commitments Expiration	90 days
Line of Credit, Maturity, Max	18 months
Operating Leases, Future Minimum Payments Due	53,803,000
Operating Leases, Rent Expense	3,800,000us-gaap_LeaseAndRentalExpense	3,700,000us-gaap_LeaseAndRentalExpense	3,700,000us-gaap_LeaseAndRentalExpense
Home Equity Line of Credit [Member]
Note 15 - Commitments and Contingencies (Details) [Line Items]
Loans and Leases Receivable, Commitments, Credit	190,400,000
Line of Credit, Maturity, Max	10 years
Letter of Credit Pledged as Collateral [Member]
Note 15 - Commitments and Contingencies (Details) [Line Items]
Deposit Liabilities, Collateral Issued, Financial Instruments	499,100,000
Capital Securities [Member] \| Flushing Financial's Capital Trusts [Member]
Note 15 - Commitments and Contingencies (Details) [Line Items]
Proceeds from Issuance of Debt				20,600,000	61,900,000
New Corporate Lease Agreement in Uniondale, NY [Member]
Note 15 - Commitments and Contingencies (Details) [Line Items]
Area of Real Estate Property (in Square Feet)	90,000
Lessee Leasing Arrangements, Operating Leases, Term of Contract	12 years
Operating Leases, Future Minimum Payments Due	24,400,000
Mortgage Loans on Real Estate [Member]
Note 15 - Commitments and Contingencies (Details) [Line Items]
Loans and Leases Receivable, Commitments, Credit	$ 68,300,000